Please help me understand various modes in which CF can be accessed. I understand that there are 3 access modes of CompactFlash card:
- PC Card ATA memory mode (uses OE-, WE-) 2. PC Card ATA IO mode (uses IORD-, IOWR-) 3. true IDE mode (complies to ATA-4)
I have following doubts:
- In PC Card ATA memory mode, how does the host access complete memory space when only 11 address pins are there (limiting addressable space to 4KB) 2. In PC Card ATA IO mode, there is one memory mapped mode and 3 IO mapped Modes. Can someone please throw light on this memory mapped IO mode inside IO mode.
- I read somewhere that CF+ card extends CF functionality beyond CF card IO modes. How?
- I read that PC Card ATA mode complies to ATA spec. Then why have another True IDE mode? (I have partial answer: TrueIDE provides DMA mode and can use existing drivers but then why can't PC Card ATA IO mode do the same?)
I have access to CompactFlash and ATA specs but not PC Card ATA spec.
Thanks for any response. Gaurav